There is a need for a stable cleaning and disinfecting wipe and article that is capable of cleaning and removing residues from soiled surfaces while simultaneously destroying undesirable microorganisms, e.g. bacteria, mold, viruses, prions and the like that colonize on common surfaces with which people come into contact, such as doorknobs, countertops, toilet seats, floors, beds, walls, and the like.
Hypohalite releasing compounds, such as the hypohalites and related compounds that release active forms of hypohalite and/or halogens, are extremely effective disinfectants capable of destroying a wide range of microorganisms. Hypohalite releasing antimicrobial compounds, and in particular the hypohalites, constitute a class of strong chemical oxidants possessing both cleaning and bleaching properties in addition to their antimicrobial properties making them superior to other disinfectants, such as quaternary ammonium biocides. The hypohalite class of chemical oxidants act to rapidly oxidize susceptible substances found in inorganic, organic and biological materials, rendering them more easily removed from surfaces, and in the case of colored or pigmented materials, bleaching them to white or colorless end products resulting in effective cleaning and stain removal from soiled surfaces. Owing to their strong oxidizing capability, hypohalites also possess inherent disinfection properties and additionally possess desirable characteristics including excellent aqueous solubility, mobility and a highly dissociative ionic nature. A further advantage of the hypohalite class with regard to disinfectancy, is the speed and efficacy with which they attack microorganisms and either destroy them or render them non-viable following very short contact times. Yet a further advantage of the hypohalites is the wide susceptibility of many different types of microbial pests to their strong oxidizing potential and essentially the absence of any known microbe to develop an effective resistance against the action of these materials.
Typically, microbiologically contaminated surfaces seldom comprise only the microorganisms themselves, but include the presence of soils and other residues, including organic, inorganic and biological residues associated with the source of the microbiological contamination. These residues, including, for example, saliva, bodily fluids, blood and common soils such as foods, oils and dirt, not only host microorganisms, but can act to shield and protect the microorganisms from the disinfectant action of non-hypohalite disinfectant materials.
One seeming disadvantage of the hypohalite class of materials is their susceptibility to decomposition, including self-decomposition and reactive decomposition owing to the interaction of the hypohalites with the substrates and materials in which they come into contact during storage, such as packaging materials, and particularly in the case of pre-wetted wipes, the material used as the absorbent carrier substrate which is impregnated with the disinfectant composition. Hence, freshly prepared solutions or disinfectant articles utilizing these materials are typically required to ensure adequate activity for ensuring effective disinfection of surfaces. Attempts have been made in the past to provide a convenient disinfectant article by absorbing a hypohalite solution onto an absorbent towel or carrier. However, prior attempts have failed to produce a hypohalite releasing disinfectant wipe with sufficient stability to ensure suitable disinfecting efficacy at time of use, particularly following typical storage times and/or less than ideal storage conditions representative of real world environments encountered in the home, office, business, hospital or field where needed.
U.S. Pat. No. 4,998,984, to McClendon, describes a premoistened disinfectant article impregnated with a disinfectant composition that may include sodium hypochlorite and is prepackaged in a liquid impermeable container. U.S. Pat. No. 5,087,450, to Lister, describes a viral wipe to remove organic material having viral contaminants from a surface which consists of a porous gauze pad lined with a non-porous flexible fluid impervious barrier layer fused to one side and impregnated with 10% sodium hypochlorite and stored in a protective foil, plastic and paper layered package. Lister notes that the 10% sodium hypochlorite solution becomes unstable within a short period of time.
U.S. Pat. No. 5,985,302, to Dorr, et al., describes a method for inactivating HIV infected blood which involves first swabbing a contaminated surface with a first aqueous calcium and/or sodium hypochlorite impregnated fibrous towlette, followed by a second swabbing with a second towlette impregnated with a neutralizing sodium thiosulfate solution. However, the Dorr et al. example exhibits poor stability and complete loss of inactivating activity even of a dry calcium hypochlorite/methyl cellulose system freshly dissolved in water to produce a disinfecting solution after only 10 days storage at 50° C. U.S. Pat. No. 6,313,049, to Heady and Wolkensperg, describes a pre-packaged fabric-saturated absorbent sheet with the U.S. food-industry legal chlorine disinfectant solution and discloses the use of cotton, paper or sponge sheets as absorbents. U.S. Pat. No. 6,387,384, to Probert and Probert, describes a prepackaged towlette bearing sodium hypochlorite and discloses the use of gauze or bandage material as absorbents.
The prior art fails to provide a stable disinfectant article that maintains acceptable stability after representative storage times and storage conditions typical of actual usage conditions encountered in the real world. For instance, most commercial product distribution channels result in products ageing several months following manufacture before being placed on sale, followed by significant delays before actually being used. During this time, products are seldom stored under ideal conditions, but rather are exposed to temperature variations typical of the home, field and industrial environment. Most significantly, the prior art fails to disclose suitable absorbent carrier substrates with acceptable stability nor a reliable means for selecting an appropriate absorbent material suitable for extended stability of aqueous hypohalite disinfectant articles to ensure reliable antimicrobial efficacy when needed.
Clearly, there remains an unmet need for an aqueous hypohalite disinfecting article with improved stability that can provide the required antimicrobial efficacy for disinfecting microbiologically contaminated surfaces, particularly following typical storage times and/or less than ideal storage conditions representative of real world environments encountered in the home, office, business, hospital or field where needed.